Use & Application Of Oxygen Isotopes In Ground Water Studies
- Naturally occurring oxygen is composed of three stable isotopes 16O, 17O, and 18O.
- 16O being the most abundant (99.762% natural abundance)
- Known oxygen isotopes range in mass number from 12 to 24.
- 16O is a primary isotope while 17O and 18O are secondary isotopes
Stable oxygen is used in
- ground water studies
- to investigate recharge,
- ground water interaction
- surface water interaction
- Paleo hydrogeologic interactions
- to estimate ground water ages
The ratio of 18O to 16O in ice and deep sea cores is temperature dependent
Thus, can be used as a proxy measure for reconstructing climate change.
During colder periods,16O is preferentially evaporated , leaving the slightly heavier and more sluggish 18O behind.
(i) Temperature change effects
Dansgard (1964) plotted the relationship between temperature (taken as the mean annual air temperature for a station) and the δ18O value.
From this he derived the graph and equation
Graph clearly shows the very strong relationship between temperature and δ18O.
This is a response to greater fractionation taking place at low temperatures than at high temperatures
(i) Altitude effects Temperature decreases with altitude. This is again a temperature driven effect.
Thus, oxygen isotopes play a major role in ground water studies which may be helpful for further researches. Its temprature dependency plays key role in its importance.